Apex domains cannot have CNAME records.
Question and response
Question
dig exepto.ru. NS
Answer
exepto.ru. 5 NS ns1.srvdns.ru.
exepto.ru. 5 NS ns2.srvdns.ru.
Authority
The response has no authority records.
Additional
ns1.srvdns.ru. 5 A 185.206.100.100
ns2.srvdns.ru. 5 A 88.212.217.180
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0